The instrument used in a submarine to see the object on the surface of the water is:

1. Periscope
2. Telescope
3. Kaleidoscope
4. Microscope

Periscopes allow a submarine when submerged at a relatively shallow depth, to search visually for nearby targets and threats on the surface of the water and in the air.

When not in use, a submarine’s periscope retracts into the hull.